Laboratory and Field Evaluation of a Chloride-free Material for - - PowerPoint PPT Presentation

Kenji Sato1, Akihiro Fujimoto1, Makoto Kiriishi2, Roberto Tokunaga1, Naoto Takahashi1 and Noriyuki Nakajima3 1Civil Engineering Research Institute for Cold Region, P.W.R.I., Japan 2Hokkaido Regional Development Bureau, M.L.I.T., Japan 3Toyama Prefectural University, Japan

Laboratory and Field Evaluation

• f a Chloride-free Material

for Snow and Ice Control

Introduction

Sodium chloride (SC) is the major deicing agent

Reasons why SC is applied:  Inexpensive  Easily available in large quantities  Highly effective in melting ice  Easy to deliver, store, and load onto vehicles Application of anti-icing and deicing agents and other measures for preventing wet roads from becoming icy are important for "ensuring safe and smooth winter road traffic".

Sodium chloride(SC)

Background and Aim of Study

There is a concern over negative impacts on the roadside environment caused by the application of chloride

Development of a new chloride-free deicing agent that does not significantly damage the roadside environment

Tests focusing on Sodium propionate(SP)  Laboratory metal corrosion test  Application test at a test track

Survey of various compounds in search for the best available deicer  Vehicles  Bridges and other roadside structures  Soil, plants, etc.

Although SC is the major deicing agent,

What is Sodium Propionate?

 General use: Used as a food preservative (i.e., fungicide)

Food: Cheese, bread, cake

Other products: Cosmetics, feed, paints, adhesives, etc.  Retail price in Japan: US$10-15 / kg US$2 / kg for purchase of 10 tons at a time  Form: Pulverized usually; Granulation possible  Freezing point Specimen (a 20%-by-mass solution) Freezing point SC

• 19.1°C

SP

• 16.1°C

SC + SP (weight ratio 8:2)

• 18.9°C

Powder Glanulated

Close up photo of an SP particle

State of SP

7mm

1) A 3.0 g of test material is dissolved in 100 cc of distilled water for preparing a test solution; 2) An iron specimen without zinc coating, which was weighed beforehand, was immersed in a solution of each test material for 24 hours and then left to dry for 24 hours; 3) The immersion-and-dry cycle was repeatedly conducted for 7 days; and 4) On the 8th day, the rust was completely removed from the specimen, and the remaining iron piece was weighed to see the difference in weight before versus after rusting. Metal corrosion test by using various deicers

Metal Corrosion Test Procedures

Metal Corrosion Test Results

Specimen Amount of corrosion (mg / dm2 × day) Distilled water 8.6 mdd SC 22.5 mdd Calcium chloride (CC) 27.5 mdd SP 0.3 mdd SC + SP(weight ratio 8:2) 4.4 mdd

In comparison to distilled water and the solution of SC or of CC, the amount of corrosion was significantly smaller for the SP solution and the SC+SP mixture with a weight ratio of 8:2.

Metal corrosion damage to vehicles and roadside structures is reduced.

Test Method

Test day January 21, 2015 Testing Location Tomakomai Winter Test Track(Length=2,700m) Civil Engineering Research Institute for Cold Region Public Works Research Institute Tomakomai Winter Test Track

Test Method

Test day January 21, 2015 Weather Fine Time 18:41 ~ 22:47 Temp.

• 6.0 ~ -3.8°C

Road Temp.

• 3.3 ~ -2.0°C

Timing of spreading Application after the track surface was frozen Test material No treatment NT SC Dry spreading SC SC + SP (weight ratio 8:2) Dry spreading SC+SP SC+SP solution (30 %-by-mass solution) (weight ratio 9:1) Wet spreading SC+SPS SC+CC solution (30 %-by-mass solution) (weight ratio 9:1) Wet spreading SC+CCS Application rate 20 g/m2 100m

Road temperature gauge KP=0.35 KP=0.45 KP=0.55 KP=0.65 t = 0.5 ~ 1.0mm

50m 50m 50m 50m 1 2 3 4 5

KP=0.75 Five test vehicles Ice film on the road surface

• 1. NT
• 2. SC
• 3. SC+SP
• 4. SC+SPS
• 5. SC+CCS

Test Procedures

(2) (1)

Road temperature gauge KP=0.35 KP=0.45 KP=0.55 KP=0.65 t = 0.5 ~ 1.0mm

50m 50m 50m 50m 1 2 3 4 5

KP=0.75 Five test vehicles Ice film on the road surface

• 1. NT
• 2. SC
• 3. SC+SP
• 4. SC+SPS
• 5. SC+CCS

Sprinkling water for making ice film on the surface Salt application

(3) (4)

Test Procedures

Skid resistance measurement 5 test vehicles traveling in the test sections

Road temperature gauge KP=0.35 KP=0.45 KP=0.55 KP=0.65 t = 0.5 ~ 1.0mm

50m 50m 50m 50m 1 2 3 4 5

KP=0.75 Five test vehicles Ice film on the road surface

• 1. NT
• 2. SC
• 3. SC+SP
• 4. SC+SPS
• 5. SC+CCS

• Developed in the U.S.
• Measures friction continuously
• Measurement wheel attached to a vehicle
• Measuring wheel offset 1-2 degrees
• Measures transverse force
• Skid resistance expressed by “HFN”

CFT

Continuous Friction Tester (CFT)

Movement direction 1-2 degrees Lateral force Measurement wheel (Tire) Skid resistance measurement principle

HFN: Halliday Friction Number 0 (no load) 100 (dry pavement)

Test Results

18:41 19:06 19:35 20:19 20:57 21:33 22:10 22:47

Summary and Future Study

• Results of the metal corrosion test

SP helps reduce the amount of metal corrosion even when it is mixed with SC.

• Results of the application test

Dry application of an SC+SP mixture as well as wet application of SC mixed with an SP solution is as effective as dry application of SC and wet application

• f SC mixed with a CC solution in increasing the skid resistance.

The research will be continued by focusing on the following topics with a view to increasing the use of SP as an deicer:  Effectiveness of SP in melting ice  Distribution and costs of SP  Negative impacts caused by SP on soil, plant, and other aspects of the roadside environment Although SP is more expensive than SC, costs can be controlled by using a mixture of SP and SC.

Thank you for your kind attention.

Kenji Sato Traffic Engineering Research Team, Cold-Region Road Engineering Research Group Civil Engineering Research Institute for Cold Region, Public Works Research Institute, National Research and Development Agency satou-k22bi@ceri.go.jp